The mechanism and applications in natural product synthesis of photostimulated nucleophilic aromatic substitution are under study, including approaches to drupacine and 11-hydroxycephalotaxine. Fomannosin and frenolicin, two mold metaboliies with known or potential biological activity are being approached by total synthesis, including model systems designed to test new quinone-based synthetic intermediates. New methodology related to a specific strategy for synthesis of the cytotoxic alpha-methylene-gamma-lactones continues to be a focal point for our work. BIBLIOGRAPHIC REFERENCES: S.M. Weinreb, and M.F. Semmelhack, "Total Synthesis of Cephalotaxus Alkaloids," Accts. Chem. Res., 8, 158 (1975). M.F. Semmelhack, et.al., "Total Synthesis of Cephalotaxus Alkaloids," J. Amer. Chem. Soc., 97, 2507 (1975).